Facilitating Interoperability Among Communication Systems via Inter- and Intra-Agency Communications Using a Shared Network

1. A method for providing contact information via a directory service (DS), the method comprising computer implemented operations of: receiving a request from a DS originator to obtain at least a portion of contact information associated with a target resource prior to establishing a communication session with the target resource; in response to receiving the request, identifying a first policy that is a DS access and/or viewing policy of the DS originator and identifying a second policy that is a DS access and/or viewing policy of the target resource; based on both the first policy and the second policy, determining whether at least the portion of the contact information associated with the target resource is authorized to be presented to the DS originator; when at least the portion of the contact information associated with the target resource is authorized to be presented to the DS originator, determining and modifying a portion of the contact information associated with the target resource for presentation to the DS originator in accordance with at least one of the policies; presenting the modified portion of the contact information associated with the target resource to the DS originator; and in response to presenting the modified portion of the contact information to the DS originator, receiving, from the DS originator, an attempt to proceed with the establishment of the communication session with the target resource.

2. The method of claim 1 , wherein at least the portion of the contact information associated with the target resource comprises at least one of the following: a resource identifier for the target resource, a group membership of the target resource, a home identifier of the target resource, a contact address of the target resource, a type of device associated with the contact address, and a type of application associated with the contact address.

3. The method of claim 1 , wherein at least the portion of contact information is a resource identifier for the target resource, and wherein presenting the modified portion of the contact information associated with the target resource to the DS originator comprises presenting a proxy resource identifier associated with the target resource to the DS originator based on both the first policy and the second policy in lieu of the resource identifier.

4. The method of claim 3 , further comprising: associating the proxy resource identifier with the target resource in the DS; and assigning, by the DS, the proxy resource identifier to the DS originator, wherein the proxy resource identifier can only be used by the DS originator that is assigned to use the proxy resource identifier by the DS.

5. The method of claim 4 , further comprising at least one of: associating the proxy resource identifier with exactly one target resource in the DS and assigning by the DS for use by one DS originator; associating the proxy resource identifier with exactly one target resource in the DS and assigning by the DS for use by a plurality of DS originators; associating the proxy resource identifier with a plurality of target resources in the DS and assigning by the DS for use by one DS originator; and associating the proxy resource identifier with a plurality of target resources in the DS and assigning by the DS for use by a plurality of DS originators.

6. The method of claim 4 , further comprising associating a timer with the proxy resource identifier such that the DS can re-associate the proxy resource identifier to a different target resource or re-assign the proxy resource identifier to a different DS originator upon expiration of the timer.

7. The method of claim 1 , wherein at least the portion of contact information is the contact address for the target resource, and wherein presenting the modified portion of the contact information associated with the target resource to the DS originator comprises presenting a proxy contact address associated with the target resource to the DS originator based on both the first policy and the second policy in lieu of a contact address.

8. The method of claim 7 , further comprising: associating the proxy contact address with the target resource in the DS; and assigning, by the DS, the proxy contact address to the DS originator.

9. The method of claim wherein the proxy contact address can only be used by the DS originator that is assigned to use the proxy contact address by the DS.

10. The method of claim 8 , further comprising at least one of: associating the proxy resource identifier with exactly one target resource in the DS and assigning by the DS for use by one DS originator; associating the proxy resource identifier with exactly one target resource in the DS and assigning by the DS for use by a plurality of DS originators; associating the proxy resource identifier with a plurality of target resources in the DS and assigning by the DS for use by one DS originator; and associating the proxy resource identifier with a plurality of target resources in the DS and assigning by the DS for use by a plurality of DS originators.

11. The method of claim 8 , further comprising associating a timer with the proxy contact address such that the DS can re-associate the proxy contact address to a different target resource or re-assign the proxy contact address to a different DS originator upon expiration of the timer.

12. The method of claim 1 , wherein the first policy includes at least one identifier, with each identifier indicating a particular target resource for which at least a portion of the contact information is authorized to be presented to the DS originator, and wherein the second policy includes at least one identifier, with each identifier indicating a particular DS originator that is authorized to be presented at least a portion of contact information associated with the target resource.

13. The method of claim 1 , wherein the communication session comprises a half-duplex push-to-talk call.

14. The method of claim 1 , wherein the communication session comprises a video communication session.

15. The method of claim 1 , wherein at least the portion of the contact information associated with the target resource is a contact address of the target resource and the request did not specify the contact address of the target resource.

16. A non-transitory computer storage medium having stored thereon a set of instructions which, when loaded into a hardware device, causes the hardware device to perform the following functions: receive a request from a DS originator to obtain at least a portion of contact information associated with a target resource prior to establishing a communication session with the target resource; in response to receiving the request, identify a first policy that is a DS access and/or viewing policy of the DS originator and identify a second policy that is a DS access and/or viewing policy of the target resource; based on both the first policy and the second policy, determine whether at least the portion of the contact information associated with the target resource is authorized to be presented to the DS originator; and when at least the portion of the contact information associated with the target resource is authorized to be presented to the DS originator, determine and modify a portion of the contact information associated with the target resource in accordance with at least one of the policies; present the modified portion of the contact information associated with the target resource to the DS originator; and in response to presenting the modified portion of the contact information to the DS originator, receive, from the DS originator, an attempt to proceed with the establishment of the communication session with the target resource.

17. The non-transitory computer storage medium of claim 16 , wherein the communication session comprises a half-duplex push-to-talk call.

18. The non-transitory computer storage medium of claim 16 , wherein the communication session comprises a video communication session.

19. The non-transitory computer storage medium of claim 16 , wherein at least the portion of the contact information associated with the target resource comprises at least one of the following: a resource identifier for the target resource, a group membership of the target resource, a home identifier of the target resource, a contact address of the target resource, a type of device associated with the contact address, and a type of application associated with the contact address.

20. The non-transitory computer storage medium of claim 16 , wherein at least the portion of the contact information associated with the target resource is a contact address of the target resource and the request did not specify the contact address of the target resource.